import pygame
from pygame.sprite import Sprite
# 继承
class Bullet(Sprite):
    def __init__(self,ai_settings,screen,ship):
        super().__init__()
        self.screen = screen
        self.rect = pygame.Rect(0,0,ai_settings.bullet_width,ai_settings.bullet_height)
        # 设置子弹的初始位置
        self.rect.centerx = ship.rect.centerx
        self.rect.top = ship.rect.top

        # 设置移动中子弹的位置
        self.y = float(self.rect.y)
        self.color = ai_settings.bullet_color
        self.speed_factor = ai_settings.bullet_speed_factor


    def update(self):
        # ""向上移动子弹"""
        self.y = self.y - self.speed_factor
        self.rect.y = self.y


    def draw_bullet(self):
        # ""在屏幕上绘制子弹"""
        pygame.draw.rect(self.screen, self.color, self.rect)
